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Author Topic: KFMIOP/KFMIRL tuning & Torque intervention  (Read 31838 times)
ddillenger
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« on: April 22, 2013, 03:32:52 PM »

Honestly, I would have liked to seen a deeper discussion of IOP and torque intervention. Seems like this would be an ideal case study. My own IOP is barely different from stock, and only in places where I have adjusted IRL. I wonder if there is something about the way I changed it that is wrong as well.


My grasp on this isn't as solid as I'd like either.

As for PRJ, I like him being critical. The only issue I have is I sometimes fear people won't post good information for fear of looking foolish.

I'm going to edit to add this:

Shane,

If someone asks me for a referral on a tuner, PRJ gets my vote every time. If phila were doing this commercially it'd be a draw between them. To say I value their opinions would be an understatement.
« Last Edit: August 05, 2014, 05:34:41 PM by nyet » Logged

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prj
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« Reply #1 on: April 22, 2013, 03:37:27 PM »

There is nothing much to discuss about IOP and IRL, it's just as the FR says.
IOP has to be the inverse of IRL, it also has to have the axis rescaled and go as high as needed, or otherwise mrfa_w will read the rightmost column and spec load will be limited.
But really, if you just generate KFMIOP with stock values using excel, you will be within 0.1% tolerance of the factory values and see that they do it exactly the same way.

KFMIRL is used to request load through MRFA, and KFMIOP is used to look up the inverse, simple as that.
The reason it's done this way is just because it saves computational time...

If you mis-tune KFMIOP, like raising values, then the ECU won't be able to reduce torque properly.
So all kind of torque intervention, such as gearbox or ESP will be off and cause heavier torque intervention in some cases...
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nyet
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« Reply #2 on: April 22, 2013, 03:40:40 PM »

There is nothing much to discuss about IOP and IRL, it's just as the FR says.
IOP has to be the inverse of IRL, it also has to have the axis rescaled and go as high as needed, or otherwise mrfa_w will read the rightmost column and spec load will be limited.

this is PRECISELY what I tried, except that I had to put all the low load areas back to stock (which isn't the strict inverse of IRL in those areas!).. btw all my low load areas are bone stock in IRL as well.

At minimum, I'm glad my understanding of IOP lines up with yours (esp the comment about saving computation time by having complementary maps) Tongue
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nyet
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« Reply #3 on: April 22, 2013, 03:41:52 PM »

If someone asks me for a referral on a tuner, PRJ gets my vote every time. If phila were doing this commercially it'd be a draw between them. To say I value their opinions would be an understatement.

Absolutely concur.
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prj
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« Reply #4 on: April 22, 2013, 03:45:44 PM »

And yet, most "pro tuners" do exactly this, for every new car they start tuning..

There's a lot of bad stuff about indeed. There's a lot of bad stuff even from this forum by some people claiming to be "pros".
My advice when looking for someone who tunes stuff is looking how many successful high powered cars they've done on stock ECU.
Maybe have a look at their website etc... because the higher powered stuff is what is hard to tune, stage 1 stuff is quite easy.

Most "pro-tuners" don't have any clue about assembly code, they just use hex pattern matching.
To have someone who can do custom assembly stuff as well as understand the internal combustion engine very well takes just the right mixture of computer science geek and petrolhead, and this is usually quite hard to find as they tend to be mutually exclusive.
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prj
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« Reply #5 on: April 22, 2013, 03:48:14 PM »

this is PRECISELY what I tried, except that I had to put all the low load areas back to stock (which isn't the strict inverse of IRL in those areas!).. btw all my low load areas are bone stock in IRL as well.

At minimum, I'm glad my understanding of IOP lines up with yours (esp the comment about saving computation time by having complementary maps) Tongue

Down low, you might want to have the IOP a little bit lower to allow some tolerance for overshoot. The internal combustion engine is a messy and imprecise thing, so mathematical models that go to the last decimal point don't always quite line up due to overshoot and undershoot Smiley

I usually don't touch the lower areas of KFMIOP, I just rescale the axis from 90-100 load up and provide a smooth gradient, so the interpolation can do it's job.
There's really no point in replacing the entire IOP table, and for many Stage 1 tunes you don't even have to touch IRL and IOP.
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ddillenger
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« Reply #6 on: April 24, 2013, 06:27:15 PM »

Forgive my ignorance, but whic maps share an axis with IOP?

My understanding is:

Rescale the IOP axis to match up with IRL. Recalculate IOP under the rescaled areas. Do the same with KFZWOP/2. Is there anything I'm missing? I'm just getting comfortable rescaling axis'.
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nyet
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« Reply #7 on: April 24, 2013, 07:38:06 PM »

Forgive my ignorance, but whic maps share an axis with IOP?

My understanding is:

Rescale the IOP axis to match up with IRL. Recalculate IOP under the rescaled areas. Do the same with KFZWOP/2. Is there anything I'm missing? I'm just getting comfortable rescaling axis'.

That's all I do.

ETA: there is one more map that shares it: KFMDS

I dont have it defined in M-box. Not sure if we care.
« Last Edit: April 24, 2013, 07:43:54 PM by nyet » Logged

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phila_dot
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« Reply #8 on: April 24, 2013, 07:53:47 PM »

Forgive my ignorance, but whic maps share an axis with IOP?

My understanding is:

Rescale the IOP axis to match up with IRL. Recalculate IOP under the rescaled areas. Do the same with KFZWOP/2. Is there anything I'm missing? I'm just getting comfortable rescaling axis'.

KFMIOP KFZWOP KFMDS

I don't really feel like debating right now, but I would love for someone to speak specifically on this subject because I tend to disagree with everyone on this subject.

The only concern is keeping mibas and misolv less than miszul and mifa less than mimax.

KFMIRL translates torque request (milsol) to spec load.

KFMIOP gives mimax from rlmax which basically caps mifa, mibas is torque from rl corrected by ignition and lambda efficiency, miopt is used in intervention, and miist is output to other controllers.

KFMIZUFIL is torque limit from wped. This is the check and balance, but pedal axis maxes at 60% and anything over is basically unchecked. This is backed up by "Level 2" which will intervene if this map is adjusted. I don't see a need to touch this map or the UM maps.

mimax_w is what could cap spec load by capping the torque request, but the load axis is rlmax, so your basically working with the last column all the time. This should never be an issue.

mrfa is that base value for mifa, but that is the extent of it's influence here.

All of the external interventions are basically percentage reductions, so unless mifa is abnormally low, you can't really mess them up.

Didn't mean to write all that...
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ddillenger
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« Reply #9 on: April 24, 2013, 08:08:02 PM »

KFMDS drag torque speed and load dependence

0x1E302

Factor X*0.001526

Time to search the FR I guess. If noone bothers to recalculate it after an axis change, I'm curious to know it's significance.
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nyet
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« Reply #10 on: April 24, 2013, 08:12:03 PM »


The only concern is keeping mibas and misolv less than miszul and mifa less than mimax.
...
KFMIOP gives mimax from rlmax which basically caps mifa, mibas is torque from rl corrected by ignition and lambda efficiency, miopt is used in intervention, and miist is output to other controllers.
...
mimax_w is what could cap spec load by capping the torque request, but the load axis is rlmax, so your basically working with the last column all the time. This should never be an issue.

All of the external interventions are basically percentage reductions, so unless mifa is abnormally low, you can't really mess them up.

I think the idea is that unless you scale the load axis UP in IOP, for a given load, mifa might be too large. Your point is that if you don't touch IOP, you are always in the last cell for rl>191, so mifa will never be too large?

Makes sense.
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Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience.
prj
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« Reply #11 on: April 25, 2013, 12:28:18 AM »

IRL has to be inverse of IOP, end of.

Example, if you are running 220 load and your IOP axis only goes to 170 and the last value is 99%.
Then anytime ME7 would like to request over 170 load it'll request 220.
It's especially bad with 1.8T where IOP caps out at 140.

This means, that it is unable to have a fine granulation from 170 to 220.
This gives problems on any sort of torque intervention as it is impossible to ramp up the torque gradually.

Side effect of this is that ESP becomes unusable on the RS4 if entire IOP map is bumped up, as a light intervention does absolutely nothing and it goes instantly to the hard cut where it cuts all your power.
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ddillenger
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« Reply #12 on: April 25, 2013, 12:48:54 AM »

IRL has to be inverse of IOP, end of.

Any chance you can post an example of a file (or the matching IOP/IRL) that has been done correctly? I understand this in theory, but experience has shown different results, particularly at low loads. It would be even better if we had the software number so as to compare the changes to the original. I know what I'm asking for is dangerously close to spoon feeding, but I really feel that my understanding would be increased given the benefit of your experience here.

As for KFMDS, are the effects of rescaling the axis without recalculating negligible as others have suggested? I assume (never safe around here) if it's involvement were significant we wouldn't get away with ignoring it when rescaling.
« Last Edit: April 25, 2013, 12:55:17 AM by ddillenger » Logged

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phila_dot
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« Reply #13 on: April 25, 2013, 06:09:31 AM »

Except that KFMIOP doesn't have that strong of an influence on spec load, unless mifa is greater than mimax. Which would trigger torque intervention from mifa != misol anyway.

DD if you rescale the axis, then you have to fix the tables, KFMDS included.
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NOTORIOUS VR
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« Reply #14 on: April 25, 2013, 07:02:28 AM »

Just an FYI, this is a split from the discussion that was happening inside the thread of "Tuned ECU files"

Carry on Smiley
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